Pore pressure prediction in laminated shaly sand reservoir: A case study of Bintuni Basin

Abstract

Pore pressure prediction has been carried out using well log and seismic velocity data to evaluate pore pressure character of the laminated shally sand reservoir in Bintuni Basin, West Papua. The majority of the thin laminated reservoir are below resolving power of logging tool. The main factor of reservoir behavior, which typically exhibits composition mineral of lithic, micaceous and glauconitic, has a strong relationship with conductive mineral. Based on total gas mud logging data, there is some potential gas reservoir. In this study, non-normal high pore pressure was identified in some intervals and designed for cases where compaction disequilibrium is the cause of fluid expansion on the compaction state of the impermeable sediments. We used Eaton’s method to estimate pore pressure gradient. We also performed seismic velocity model analysis to estimate the effective stress using empirical Bowers and Terzaghi method, where horizontal and vertical pressure data were distributed using probabilistic neural network method. Our analysis on the pore pressure distribution map, which is combined with the time structure, shows that the correlation of non normal pore pressure is found not only in height structure but also in the low structure, particularly at the southern part of the study area.